Work is to continue upon materials and techniques which may be useful in the construction of artificial placentas. The particular problems posed by long diffusion distances through boundary layers in larger models will be closely examined. Work with artificial capillaries will emphasize commercially available cells and special models constructed from artificial capillaries in our laboratories. The models will be used to examine the effect of alkalosis on the ability of the model to transfer oxygen. In a parallel phase of investigation we will attempt to describe the effect of macroaggregates of fluorocarbon fluid suspended in water on model oxygen transfer.